Falkmanite Mineral Data

General Falkmanite Information

Chemical Formula:

Pb5Sb4S11

Composition:

Molecular Weight = 1,842.83 gm

Antimony 25.77 % Sb

Lead 55.09 % Pb

Sulfur 19.14 % S

______

100.00 %

Empirical Formula:

Pb_4.9Sb_3.9S₁₁

Environment:

Similar to boulangerite. New data from synthetic material suggests meneghinite is closer in structure.

IMA Status:

Valid Species (Pre-IMA)

Locality:

Bayerland mine, Pfaffenreuth, Bayern (Bavaria), Germany. Link to MinDat.org Location Data.

Name Origin:

Named for O.C.A. Falkman.

Name Pronunciation:

Falkmanite + Pronunciation

Falkmanite Image

Images:

Falkmanite

Comments: Metallic black platy striated falkmanite, with bronze luster in spots.
Location: Grube Bayerland, Waldsassen, Bavaria, Bayern, Germany. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Falkmanite Crystallography

Axial Ratios:

a:b:c =2.7458:1:1.4485

Cell Dimensions:

a = 21.626, b = 7.876, c = 11.409, Z = 4; beta = 96.12° V = 1,932.18 Den(Calc)= 6.33

Crystal System:

Monoclinic

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.734(1)(312), 2.75(0.6)(603), 1.9(0.53)(340), 1.895(0.51)(334), 3.171(0.49)(122), 3.284(0.48)(512), 3.147(0.43)(222), 3.25(

Physical Properties of Falkmanite

Cleavage:

{???} Good

Color:

Lead gray, Pink brown.

Density:

6.31

Diaphaneity:

Opaque

Hardness:

2-3 - Gypsum-Calcite

Luster:

Metallic

Streak:

brownish gray

Optical Properties of Falkmanite

Optical Data:

Calculated Properties of Falkmanite

Electron Density:

Bulk Density (Electron Density)=5.34 gm/cc
note: Specific Gravity of Falkmanite =6.33 gm/cc.

Fermion Index:

Fermion Index = 0.12
Boson Index = 0.88

Photoelectric:

PE_Falkmanite=1,094.38 barns/electron
U=PE_Falkmanite x rElectron Density=5,839.40 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Falkmanite is Not Radioactive

Falkmanite Classification

Dana Class:

03.05.02.02 (03)Sulfides - Sulfosalts

(03.05)where 2.5 < z/y < 3 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(03.05.02)Dana Group

03.05.02.01 Boulangerite Pb5Sb4S11 Unk Ortho

03.05.02.02 Falkmanite Pb5Sb4S11 Mono

Strunz Class:

02.HC.15 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.H - Sulfosalts of SnS Archetype

02.HC -With only Pb

02.HC.15 Boulangerite Pb5Sb4S11 Unk Ortho

02.HC.15 Falkmanite Pb5Sb4S11 Mono

02.HC.15 Plumosite* Pb2Sb2S5 Mono

Other Falkmanite Information

References:

NAME( Dana8) PHYS. PROP.(EurJMin, v 13, p 411)

See Also:

Links to other databases for Falkmanite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Ecole des Mines de Paris
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info

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Ask about Falkmanite here :
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Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Falkmanite Specimen Label here :

Falkmanite

Pb5Sb4S11
Dana No: 03.05.02.02 Strunz No: 02.HC.15
Locality:

Notes: